Introduction Flashcards
What different types of microorganisms are there?
Bacteria (Bacteriology)
❖ Viruses (Virology)
❖ Fungi (Mycology)
❖ Parasites (Parasitology); a. Helminths (Helminthology) b. Protozoa
(Protozoology)
❖ Algae (Phycology or Algology)
❖ Toxins
Characteristics of Bacteria
➢ Simplest Unicellular organisms (0.2-4µm)
➢ Genetic material in form of DNA
➢ Multiply by cell division
➢ Move using flagellae and pili
➢ 3 basic shapes: cocci, bacilli, spiral
➢ Most common cause of disease in humans
Characteristics of Viruses
Smallest infectious agent (20-300nm),1/100th size of bacteria
Can only be seen with powerful electron microscopes
Not capable of independent replication
Many different species
Can cause severe chronic disease eg HIV or acute life threatening disease e.g.
COVID-19, Ebola (viral haemorrhagic fever)
Can cause trivial infections e.g. rhinovirus (common cold)
Characteristics of Algae
1µm to several cms
Unicellular to multicellular
Reproduce asexually
Only a few unicellular species cause
human diseases
Some produce toxic substances
Different types of parasites
a. Protozoa
b. Helminths (worms)
Protozoa characteristics
a. Protozoa
Unicellular
Smallest 2-200µm
Live independently or as parasites
Few cause human diseases
Leading cause of death in developing
countries
In 2019, 229 case of malaria worldwide
(WHO,2020
Helminths characteristics
Helminths (worms)
Multicellular
Size from microscopic to 20 metres long
Need host to complete life cycle
Have both male and female organs
Cause human disease
Fungi characteristics
Large complex organisms
➢ production mainly asexual, some sexual
➢ 2 main forms
▪ Unicellular - yeast
▪ Multicellular - moulds and mushroom
➢ Source of antibiotics and toxin
➢ Cause superficial fungal infections
➢ Severe invasive fungal infections
Techniques for
studying
microorganisms
Microscopic methods
(Gram staining, SEM..)
Culture methods
(morphology, colony
appearance..)
Molecular and
immunological methods
(Elisa, PCR, real-time PCR..)
What is normal microflora
The term used when
referring to the diverse
species of microorganisms
that consistently inhabit
the bodies of healthy
animals/humans
Thousands of different
microbial species
colonise the GI tract.
❖ Each person has a unique
and relatively stable
intestinal microbiota.
What is the
microbiome?
The microbiome: the balance of microbes
(e.g. bacteria) that live in your body.
Over 40,000 species identified to date.
The average human microbiome weights
2.2kg.
Amount of DNA owned by our microbiome is
200 times our own DNA.
We should not be referring to ourselves as
‘me’, rather ‘us’ would be a better description
How does the microbiome start?
It was thought that babies were sterile in their
mother’s womb, and they were first exposed
to microbiome in the birth canal.
However, we now know that the placenta
has its own microbiome, and that our lifelong
microbiome balance is started at the
moment of conception.
The first species of the microbiome are
received during pregnancy. This is why it is
important to plan pregnancy, and to ensure
the mother is in a good state of healt
How does it start?
Birthing
The next stage of microbiome conditioning is birth.
➢ As the baby passes down the birth canal, its face, eyes,
ears and mouth are covered in secretions from the birth
canal, which gives the baby a heavy dose of his lifelong
microbiome.
➢ 3 weeks before birth, the mother’s body will populate the
birth canal with billions of beneficial bacteria and yeasts, in
preparation for the baby to swallow and set the standard
for health.
When do problems occur with the microbiome?
The baby is premature, and the appropriate
microbiome has not been placed in the birth canal
The mother is on antibiotics before or during the birth
The baby is born by caesarean
Babies who are born via caesarean, have a microbiome that is 17
similar to that of the surgeons hands. Even as adults, people
born via caesarean show distantly different gut microbiome to
those who were born via vaginal birth.
➢ C section babies are colonised by Staphylococcus and other
hospital bacteria and have much higher rates of eczema,
asthma and other immune conditions
microbiome transmission
3rd stage
Skin to skin contact transfers the
microbiome of the skin from the mother to
the newborn skin.
Hence why skin to skin contact is important.
If we miss out this vital stage, the baby can
pick up the microbiome from the
environment around them.
